Fuel pump for engines



E. A. JOHNSTON ETAL FUEL PUMP FOR ENGINES June 23, 1942.

Filed April 20, 1940 6 Sheets-Sheet 1 IN ENTORS EAJoHNsToN RE. PETERSONBY- MG AW'Y.

June 23, 1942. E A. JOHNSTON ETAL FUEL. PUMP FOR ENGINES Filed April 20,1940 6 Sheets-Sheet 2 mm W 1 A s E W] n- RLPETERSON ATI'Y.

June 23, 1942. E. A. JOHNSTON ETAL FUEL PUMP FOR ENGINES Filed April 20,1940 6 Sheets-Sheet 3 INVENTORS EAJoHNsToN REPETERsoN BY MO.

ATTY.

June 23, 1942.

E. A. JOHNSTON EIAL FUEL PUMP. FOR ENGINES Filed April 20, 1940 6Sheets-Sheet 4 N N mmm 0MB T H J P M ER 2 mm.

Mum-FM ATT'Y.

June 1942- E. A. JOHNSTON ET AL 2,287,478

FUEL PUMP FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 5 INVENTORS IEAJOHNSTON RE. PETERSON BY P'QMQPW J1me 1942- E. A. JOHNSTON ETAL2,287,478

FUEL PUMP FOR ENGINES Filed April 20, 1940 6 Sheets-Sheet 6 INVENTORSEAJOHNSTON RE. PETERSON Patented ame 23, 1942 a at EdwardA. Johnston,Chicago, and Raymond E.

Peterson, Riverside, Ill., assignors tc linternational Harvester companya corporation of New Jersey Application April 20, 1940, Serial No.330,75d

20 Claims.

This invention relates to fuel injection pumps for internal combustionengines of the Diesel type.

One of the principal objects of the present invention is to provide afuel pump for a multiple cylinder engine in which a single injectionplunger is utilized for injecting the fuel to a plurality of cylinders.

Another object is to provide a simplified drive mechanism for a pumpconstruction utilizing asingle injection plunger and a plurality oftimed delivery valves for delivering the charges of fuel in timedrelation to independent cylinders.

Another object is to provide a simplified govfor the different unitswith the use of a minimum number of parts and bearings.

Another object is to provide a pump construction in which the essentialparts areformed as removable units which can be readily removed forservice or replacement.

Another object is to provide a low pressure fuel supply pump as aseparate unit cooperatively arranged with respect to the main pump drivemechanism so as to be driven thereby.

Another object is to provide a Diesel injection system with scavengingmeans continuously operable to withdraw leakage oil from the pump andthe associated parts thereofand to return it to the supply tank withoutcreating sub-atmospheric pressures in any of the parts from which theleakage oil is withdrawn.

objects of the invention have been accomto, operate the governor shaftat four times the speed of the cam shaft. This high speed rotation oftwice the engine speed is very satisfactory for operating a centrifugalgovernor. The speed is also ample to give sufflcient plunger strokes ofthe injection plunger to supply all .of the cylinders with fuel chargesby means of a single plunger.v The injection plunger cylinder andhousing, therefore, is formed as a special unit removable as such fromthe'pump casing. The

application, Serial Number 330,749, filed April 20, 1940. Distributorvalves-are also mounted in a unit assembly which can be readily removedfrom the pump casing. The low pressure fuel supply pump and thescavenging pump are formed as a single unit readily removable from thecasing.

The above brief description gives the general arrangement of the partsmaking up applicant's improved fuel injection system.

In the drawings:

Figure 1 is a diagrammatic view showing the exterior outlines of a pumpunit embodying the invention and the fuel lines connecting the supplytank and the fllterwith the pump;

Figure 2 is a side elevation of the pump unit with the attaching housingat the end removed and with the side of the casing wall broken away insection to show the adjacent parts of the internal mechanism;

Figure 3 is a vertical section taken substantially on the center line ofthe governor and'plunger driving shaft with the distributor valvemechanism shown in elevation;

Figure 4 is a vertical section taken on the line 4-4 of Figure 3;

Figure 5 is a vertical section taken on the line 55 of Figure 3;

Figure 6 is a section taken on the line 66 of Figure 4;

Figure '7 is a section taken on the line 'I-1 of Figure 4;

Figure 8 is a. vertical section taken on the line 8-8 of Figure 7;

Figure 9 is an end view of the primary fuel supply pump unit in thenature of a section taken on the line 9-9 of Figure 2;

Figure 10 is an end view of the same unit from the other end;

Figure 11 is a horizontal section taken on the line IIH of Figure 9;

Figure 12 is a section taken on the line l2-l2 of Figure 9; 4

Figure 13 is a section taken on the line I3-II of Figure 10;

Figure 14 is a top plan view of the main pump casing with the cover,distributor block unit and plunger unit removed;

Figure 15 is a section taken on the line |5--l5 of Figure 14;

Figure 16 is a section taken on the line l6--i6 of Figure 15;

Figure 1'7 isa section taken on the line "-51 of Figure 15; and,

details of this unit are covered by the co-pendin 56 Figure 18 is avertical section taken through the center of the plunger unittransversely of the pump casing.

In the drawings, the main pump casing, or

- housing, is formed as a casting, openings be- This type ofconstruction is usually referred to as flange mounting," all of thedrive construction being enclosed. A transverse, vertical partition 24divides the pump casing into two compartments. Said partition is ofsuillcient thickness to provide a vertical bore 25 in which the pumpplunger unit, to be hereinafter described, is mounted. The bore '25 isuniform for a sub stantial distance, extending downwardly from the topface 26 of the casing 20. A second bore 21 of a substantially smallerdiameter extends beyond the bottom of the bore 25 into the interior ofthe casing. An undercut channel, or recess, 28 is provided at the bottomof the bore 25 in the radial distance existing because of the differencein bore. Said channel forms an oilcollecting and transfer means, as willbe hereinafter described.

At one end of the casing 20 a drive shaft 29, which is adapted to beconnected to drive mechanism from the engine by means of a drivingvelement 30 rigidly keyed thereon, extends into the casing through a ballbearing assembly II diagrammatically shown, fitted in a bore 32 and heldtherein by suitable retaining means. Said shaft extends within thecasing terminating in a ball bearing assembly 33 diagrammatically shown,mounted in a, bore formed in the partition member 24. A plurality ofcams 34 are formed on the shaft 29, each of said cams engaging the headportion of a tappet member 35 mounted for reciprocation in a bore 36extending upwardly through the top wall 26 of the casing terminating inan enlarged bore 31. An oil-collecting channel It is formed in theannular space provided by the difference in diameters of the bores 36and 31. Said channel has an upwardly directed edge which acts as ascraper to remove oil from the surface of the tappet member 35. Adrainage channel 29 connects each of the channels 38 and extends at an.angle downwardly. as shown in dotted lines in Figure 3 and in fulllines in Figure 14. The leakage oil collected by said drainage meansflows into the bore 25 collecting in the channel 28, previouslydescribed.

A gear 40 keyed on the shaft 29 drives a gear 4i mounted on a combinedgovernor and plunger driving shaft 42 in a speed ratio of one to four.The shaft 42 extends through a ball bearing assembly 43 showndiagrammatically, mounted in a bore 44 formed in the end wall of thecasing and retained therein by the mounting member 23. Said shaft alsoextends through the center partition 24 of the casing, being rotatablymounted therein by a ball bearing assembly 45, shown diagrammatically,mounted in a bore 48.

Beyond the partition 24 the shaft 42 is formed with an eccentric 41 onwhich a needle bearing assembly 48 is mounted, the needles contactingthe eccentric 41 and the shell forming a drive the bore ll.

assure means for englllinl atappet cup 40 mounted for reciprocation inthe bore :1.

Suitable means including a nut 44 are providedforretainingtheneedlebearingassemblyinpositionon theeccentric 4l.Areduced end portion ll oftheshaftflextendingbeyondthenutllisformedsquareincrosssectiomasbestshown inFigure5,toengagewithdrivingrelationa coupling member If pinned on a shaft II.The shaft it drives the low pressure fuel supply pump and the scavengingpump, as will be described in detail.

. The low pressure primary fuel supply pump for transferring fuel fromthe fueltank to the injection plunger, and the scavenging pump areformed in a single casing l4. At the outer end a cover plate ll closestwo intersecting bores It and I1,- as best shown in Figure 9, in whichpump gears II and It are mounted in pumping engagement with each other.The gear II is keyed on the shaft 53. The gear II is free to rotate on ashaft I. A fuel inlet compartment II is formed in the casing incommunication with the bores II and IL; A conduit 82 communicating withthe compartment it leads to the sidewall of the casing where it isconnected by a fitting to a supply conduit I leading to the bottom of afuel supply tank '4, as shown in Figure 1. A fuel delivery compartmentformed by a bore 4| communicates with the, bores It and I1 to form anoutlet. Said bore is connected by a conduit 62 with the top side of thecasing where it is connected by a suitable fitting with a discharge lineOI leading to a filter II, as shown inFlgure 1.

It is necessary that a supply pump be provided which at all times pumpsfuel in a quantity greater than is utilized by the injection plunger andat a uniform pressure. For that reason, as shown in Figure 12, a by-passconduit '1 is connected to the conduit '84 and to a bore '0communicating with the inlet compartment I. A pressure relief valve itis mounted in the bore 68, being held in position by a compressionspring ll. Said valve regulates the prmsure in the discharge linefromthe supplypump, returning the excess fuel'to the'inlet side of the pump.

The scavenging pump is formed by intersecting bores." and 12 extendinginto the casing 54 from the end opposite he location of the supply pump.A gear'll moun on the shaft I3 is located in A mating gear 14 located inthe bore I2 is mounted on the shaft 20. As shown in Figures 10 and 12,an inlet compartment II is provided in communication with the bores IIand 12. A cover plate II extending over the face of the casing at thescavenging pump end thereof, closes the pump compartment, it being heldin position by cap screws one of which is shown in Figure 3. A bore'I'I, shown in Figure 12, forms a communication between the drainagesystem of the pump casing, which will be further described in detail,and the inlet compartment 15 of the scavenging pump. An outletcompartment I8 communicating with the bores H and 12 is connected by aconduit II and a conduit II with a boss M to which a return fuel line 22is connected by a suitable fitting, as shown in Figure I. Said returnline extends into the tank terminating above the highest liquid leveltherein whereby at no time will oil drain back through the return lineinto the pump.

The main drainage channel 3! leading from the distributor valves, andthe channel 24, located at the bottom of the bore 28, have already beenaaa'ravs described. A transverse bore 93 intersects the channel 28, asshown in Figures 3, 14, and 15.

Said bore extends downwardly at an angle, as shown inFigure 15, theupper end being plugged and the lower end communicating with a verticalchannel formed by a bore 95 shown in Figures 15, 16, and 17. The bottomend of the bore 95 is bore 95 near its lower end and connects ,with abore 9I shown in Figure 16. Said bore registers with the opening II inthe cover plate 16, thereby drained by gravity into the channelsprovided forthat purpose.

The injection plunger unit is fitted into the bore 25. The housing ofsaid unit consists of a lower sleeve member I and an upper enclosuremember II. The sleeve member is provided with a shoulder at the topwhich centers the unit in the bore 25. A flange I02. at the-top plugged.A transverse bore 96 intersects the of the sleeve member seats onthe'surface 26 of the casing. The sleeve I00 is provided with a reducedlower end portion I03 whichextends within the tappet cup 49. A generallycylindrical piston control member I04 is provided with'an upper bearingshoulder I06 fitted in a bearing surface I01 formed at the upper end ofthe sleeve member I00. The lower end of the member I04 is of a smallerdiameter to conform to the shape of the sleeve I00 and is provided witha bearing portion I08 fitted for rotation in a bearing surfaceprovided-at the lower end of the sleeve I00. Said sleeve is cut awayintermediateits ends to provide for the engagement of a control rack I09with gear teeth IIO formed around the intermediate portion of thecontrol member I05.

An injection plunger III is mounted for rotation and reciprocation in abore II2 formed in a cylinder member H3. Said member is provided with ahead portion II4 fitted in an annular recess H5 formed in the flange ofthe sleeve member I00. The piston member is supported entirely from itsflanged head portion, the remainder of the member being suspended out ofcontact with the control member I04.

The piston III is provided with a plurality of lugs H6 engageable withspline-like grooves. III formed in the .lower end of the piston controlmember I00. This construction provides for reciprocation of the plungerwith respect to the control member and connects the members for rotationtogether whereby the angular position of the piston may be adjusted bymovement of the control member I08. I v

Thelower end of the plunger III is provided with a head II8 on which aspring retainer H9 is mounted. A compression spring I20 abuts theretainer H9 at its lower end and seats at its upper end against ashoulder formed at the bottom of the sleeve member I00. The spring I20is located entirely within the tappet cup 49 and the head II8 of theplunger abuts the bottom of the cup thereby determining the pistonposition.

The upper end of the plunger III is formed with an annular channel let,a vertical channel I22, and a spiral fcut ofi channel I23 Joining thevertical and the annular channels. This type of piston is well known inthe prior art, being utilized to meter the fuel injected bythe plungerdependent upon the position of the spiral cut-0E portion'with respecttoinlet and by-pass openv ings in the wall of the cylinder.

Figure 3 shows the construction of the inlet and by-pass ports for thepump plunger. The head portion I02 of the piston member is formed with apair of recesses I24 extending downwardly from the top surface of themember. Transverse bores I26 extending axially through the head portionintersect the recesses I24 and terminate in the cylinder bore. Screwplugs I26 are fitted to seal the outside ends of the bores, recesses I27being formed in the head portion to accommo ,date the screw heads whenthe piston member is dropped into position. The particular constructionof the injection unit including the delivery of fuel thereto andtherefrom, and the piston control construction are covered by theco-pending application Serial Number 330,749, filed April 20, 1940, andare described here only in so far as is necessary to make a complete andadequate showing of the invention of this application.

A spacer member I29 seated on the top of the cylinder member II3contains fuel supply conduits'in the form of bores I29 and asubstantially central bore I30 which provides a guide .for a dischargevalve I3I. The head of said valve is "seated on the top of the spacermember and is held against opening until the required pressure isobtained by a compression spring I3I'. Said spring fits in an alinedbore I32 formed in a second spacer member I33 mounted on the spacermember I3I. As best shown in Figure 18, discharge means from the plungerunit are provided by a screw threaded member I34 threaded into a boreformed in the spacer member I33 communicating with the vertical boreI32. The member I34 is formed with an internal channel I 35communicating with a channel in a connecting member I36 held in positionagainst the spacer member I33 by the member I34 with the use of suitablesealing gaskets.

The cover or housing member IOI, previously referred to, is providedwith an internal bore of the same diameter as the external borev of thespacer blocks and the head portion of the piston I I4. Said member alsohouses a filter I31 through which fuel passes from an inlet coupling I36before passing downwardly to the supply ports of the cylinder. Themember IOI is provided with a flange I39 by means of which the entireunit is secured to the casing 20 by means of student.

threaded into a bore I39 in the casing 20 as shown in Figure 14. A fuelsupply conduit I40 leading from the filter 66 connects with, thecoupling I36 tosupply-filtered fuel to the final filter I31. I

The connecting member I36 which is provided with the internal conduit I,as shown in Figure 2, leads to the fuel distributor unit. Said unitconsists essentially of a lower valve carrying block I42 and adistributor block I43. Said blocks are rigidly secured together with theabutting faces lapped to form a fuel-tight joint.

As shown in Figure 7, fuel under injection v pressure from the injectionplunger enters: the valve block I42 through a threaded securing andconduit member I43. Passing through a transverse conduit I44, the fuelpasses upwardly through a conduit I45 into a bore I46 formed in into thedistributor block. Each of said bores communicateswith a vertical bore I5I extending vertically entirely through the valve block I42. Adistributor valve I52 is mounted for reciprocation in each of the boresI5I. The lower end of each valve is positioned to be engaged by one ofthe tappet members 35, previously described. The head portion I 55 ofeach of the valves is provided with a seat adjacent the top of the boreI5I and is held against the valve block in seated position by acompression spring I53 located in the bore I58. It will be noted thatthe valve member is cut away adjacent the top to form an annular spacetherearound below the head portion I53. Fuel delivered to said spacewhen the valve is opened is delivered through an angular conduit I54 toa vertical con duit I55 extending upwardly through the distributor blockI43. Each of the conduits I55 is in communication with a fitting I55threaded into the top of the distributor block.

To provide a dust-tight enclosure for the distributor unit, a housingI51 is mounted over the top of the casing 28. The fittings I55 and theinlet connection I38 of the fuel plunger unit project through openingsin the top of said cover.

A conventional fly-ball governor is shown mounted on the shaft 42. Theweights I58 are pivoted on a carrier I59 keyed on the shaft 42. Theentire governor construction may be of any conventional type and has notbeen shown in detail. Force exerted by the fly-balls, or weights, I58,is exerted against a sleeve I58 rotatably and slidably mounted on theshaft 42. Said sleeve abuts a ball-bearing assembly I8I adapted totransmit the thrust of the governor to trunnion pins I52, as best shownin Figure 4, carried by a rockable control member I53. Said member ismounted on a shaft I54 carried by roller-bearing assemblies I55 and I55suitably mounted in bores formed in the side walls of the casing 28.

The control member I53 is provided with an upwardly extending arm I55 atone side of the casing, as best shown in Figure 2, which is formed witha generally circular head portion I55 located between two thrustportions I51 of the control rack I89, previously described. Said controlrack is mounted for reciprocation in the central partition 24 of thecasing. At the end opposite the control member the control rack I85 isprovided with an adjustable stop mechanism I58 adapted to abut a stop inthe form of a boss I58 on the casing wall to limit the maximum amount offuel which can be injected by the pump.

The control member I53 is also provided with an upwardly extending armI59, shown'in Figures 3, 4, and 5, to which a tension spring I18 issecured. Said spring is secured at the other end to a lever I1I rigidlysecured to a shaft I12 extending transversely of the casing. Said shaftcarries an adjusting arm I13 by means of which the tension on the springI18 may bemanually adjusted. To provide a maximum position, anadjustable stop mechanism I14 is located at one end of the casing 28engageable with an extenassrs sion of the lever III beyond theconnecting point of the spring I18.

Although the operation of certain units of the fuel injection system ofthis invention have been explained in connection with the description ofthe component parts, a complete operation will now be described. a

Fuel in the supply tank 54 is delivered through the conduit 55 to theinlet compartment 5| of the low pressure primary fuel supply pump. Saidpump, being of a geartype, has a positive'displacement depending on thespeed of rotation of the driving shaft. The pump is built so that thisdisplacement is sufficient to pump a larger supply of fuel than is usedat any time by the injection system, the excess fuel being-by-passedthrough the conduit 51 and the valve 55 back to the inlet ofthe pump.The spring 15 acts on the valve 55 as a pressure regulating meanswhereby the pump supplies fuel under a constant pressure to the conduit55 leading to the oil filter 55. From said filter fuel passes throughthe conduit I45 through therllter I 31, the bores in the spacer membersI33 and I25, and into the recesses I24 formed in the flanged upperportion of the cylinder member II5.

From the crankshaft 'of the engine through suitable conventionalgearing, not shown, power is transmitted to drive the primary shaft ofthe unit, which is the cam shaft 29, and through the gears 48 and H thesecondary shaft of the unit, which is the governor drive and plungeroperating shaft 42. With a four-cylinder pump, as illustrated, the camshaft is driven at a speed one-quarter of the plunger operating shaft inorder toprovide an inJection stroke for each of the distributor valves.In a two-cylinder pump it will be necessary to drive the plunger shaftat only twice the speed of the cam shaft. There is, however, a distinctadvantage in driving the shaft on which the governor is mounted at ahigh speed, as greater power and better operating characteristics can beobtained from a centrifugal type of governor operating at high speedsThe eccentric 41 of the plunger driving shaft 42, through the needlebearing assembly 45, drives the tappet cup 49 which in turn engages thebottom head portion II5 of the plunger III. Said plunger is held againstthe cam by the spring I28 and is adjusted to vary the effectiveinjection stroke by means of the control rack I89 operatingin engagementwith the gear III on the control member I54. As pointed out in thedescription, said control member is provided with axially spaced bearingportions which give accurate allnement of the member with a minimum ofbearing surface, allowing the governor mechanism to act with a minimumof frictional resistance. The provision of a reduced end portion I onthe sleeve member I55, which carries the injection lunger unit, allowsthe tappet cup 45 to extend upwardly over the lower end of the sleevemember. This construction reduces the overall height of the unit whilepermitting the use of a spring of suitable length and a tappet cup withsufficient bearing surface.

The injection plunger III is of a conventional construction known as thepiston control port type. At the bottom of the stroke. fuel is drawn inthrough bores I25 intersecting the I24 and the cylinder. As ,the plungerrises on the injection stroke. the top edge of the piston first passesover and cuts of! communication with the supp y p rts. As the strokecontinues, fuel is delivered past the valve I3I into the conduit I4Ileading to the distributor unit. When the curved wall of the pistonpasses over one of the inlet ports, fuel is by-pa ssed down through thevertical slot I2I relieving the pump of pressure and stopping thedelivery of fuel. 1

Fuel delivered'to the distributor unit through the conduit I44, as shownin Figure '7, passes upwardly by the valve I41 into the longitudinalconduit I49 which supplies each of the bores I50 with fuel underpressure at each stroke of the injection plunger. The valve I41 acts tocontrol pressure in the common conduit I49. Said valve does notopenuntil the pressure has reached an amountdetermined by the spring I46 andcloses as soon as the pressure drops on the injection plunger side ofthe valve.

The valves I53 in the bores I50 are opened in timed relation by the cams34 on the shaft 29. Said cams, as will be noted by inspection of Figure4, cover only a small angular portion of the relatively large portion ofthe shaft 29 which engage the tappets 35. It is necessary in aninjection engine of this type to deliver the fuel at a high rate and ata high pressure to the injection valve, and to cut off the pressure andsupply almost instantaneously at the termination of injection. For thatreason, the valves I52 are opened very rapidlyat the proper time and arealso closed very rapidly. There is an important advantage in thedistributor type mechanism of this type with utilization of a singleplunger over the conventional injection system utilizing a separateinjection plunger for each cylinder. It will be noted that the eccentric41, which drives the injection plunger, is formed as a cylinder of arelatively large diameter. This construction provides for raising thepump plunger at a comparatively low rate of speed and for returning theplunger at the same rate. It is possible with a distributor valve unitto operate the plunger in this manner, as the valve which delivers thefuel to the injection nozzle may not be opened until the build-up ofpressure in the system is sufiiciently high to provide for properinjection regardless of the speed of the plunger and its distance oftravel. The possibility of using a true eccentric for the pump plungerresults in a piston travel which does not at any time exceed the pistontravel on a multi-' ple cylinder pump utilizing direct injection, al-

though in the case of a four-cylinder engine the pump plunger travelsfour times the total dis tance of travel of any one plunger in amultiple plunger injection pump.

It will be understood that the drive shaft 29 for a pump unitconstructed for a four-cylinder engine of the four-cycle type operatesat half engine speed, giving two injections'per revolution of theengine. The plunger driving shaft 42 operates at four times the speed ofthe shaft 29 or at two times the speed of the crank shaft of the engine,giving two injections per engine revolution.

The governor construction for controlling the quantity of fuel injected,as illustrated in the drawings, is of a conventional type, the basicprinciple being the control of the rack I99 by centrifugal governorweights I58 acting in opposition to the spring IIOon the control memberI66. The mounting of one end -of the spring on the manual adjustablelever I'll provides means for setting for different speeds of operation.The adjusting mechanism I58 at the end of the control rack, providesmeans for adjusting the maximum injection of fuel as determined by theangular position of the injection plunger II I.

Although injection pumps of this type are made of the finest materialsavailable and the parts are precision fitted, there is always a certainamount of leakage past the fitted parts, increasing with wear. It hasbeen customary to provide means for draining the leakage fuel outsidethe pump housing and allowing'it to drip to the ground or be collectedand discarded. In the pump of this invention'provision has been made forcollecting the leakage fuel and return ing it to the fuel supply tank.The valves I52 fitted in the bores I5I necessarily withstand fuel at theinjection pressures. There will therefore be some leakage past thesevalves into the recesses 38 at the bottom of the bores 31. The recessesare formed to provide knife-like edges which scrape the walls of thetappets 35 to remove fuel therefrom and prevent its passing downwardlythrough the bores I36 into the pump casing. Leakage fuel collected atthe valves passes downwardly through the channel 39 into the bore 25collecting in the channel 28 at the bottom thereof. Said channel is alsoshaped to remove fuel from the walls of the tappet cup 49. Inspection ofFigure 18 will show that any fuel leaking past the plunger III willcollect in the tappet cup 49 and overflow into the channel 28.

The leakage fuel collected from both possible leakage sources, as abovepointed out, drains by gravity through the conduit 93 which, as bestshown in Figure 15, intersects the channel 28 downwardly through theconduits 95, 96, 91, and 11 into the inlet chamber 15 of the scavengingpump, as shown in Figure 12. Said pump returns the leakage fuel to thefuel supply tank through the conduit 82, as shown in Figure 1. As thescavenging pump is of a capacity greater than the normal amount ofleakage, an air line 99 is connected to the top of the fuel supply tankabove the liquid level therein, and to the engine of the scavenging pumpas shown in Figure l and Figures 16 and 17. This is an important elementof the scavenging system as the creation of a partial vacuum in thecollection conduits of the scavenging system would be very undesirable,acting to increase the fuel leakage and to draw lubricating oil past thetappets 35 and past the tappet cup 49 into the scavenging system.Another detrimental effect would be the drawing in of air through theseals and casing into the interior of the pump casing. Such air alwayscontains dirt which is detrimental to the life of the wearing parts ofthe pump.

A general inspection of the fuel pump of this invention will show itsextreme simplicity and accessibility for assembly and service. Thecasing 20 is such as to permit ready assembly of the drive shaft 29,which is inserted through one end thereof, and the driving shaft 42which is inserted from the same end as a unit with the eccentricgovernor and the -ball bearings assembly. It is wholly necessary tomount the control member I53 and the spring control structure, includingthe lever Ill and the shaft I12, through openings in the casing. Thecenter partition 24 of the housing provides means for mounting the innerend of the shaft 25 and is also of suflicient thickness to provide theplunger bore. 1 The tappet cup 49 is inserted from the top of the casingand the injection plunger unit is entirely assembled as a unit beforebeing mounted in the casing. Referring to Figure 18, the sleeve memberill and the housin'gf'member it! enclose as'a un'it' ofjparts of theinjection plunger 'mechani'sm. specific construction is covered 'by thecopending application above referredto, However; the unitconstructionalso forms a part of the presentinvention.

The distributor mechanism isformed as a unit including all of the partsof the" assembly within the two blocks 2 and I". These blocks may beremoved as a unit for replacement or repair;

It will be seen that the fuel injection system as described isoutstandingly simple and that it is composed of removable units whichcan be assembled rapidly and with accuracy and can be removed forreplacement or repair. Although only certain preferred embodiments ofthe different units have been illustrated, it is to be understood thatapplicant claims as his invention all modifications falling within thescope of the appended claims. j

What is claimed is: v j" n 1. In a fuel injection pump, having a casing,a high pressure injection plunger mounted there-' a in, a driving shaftand in combination there'- with, a low pressure fuel supply pump mountedon the casing, means for supplying vfuel to the inlet of said pump,means for conducting fuel under pressure from the pump tothe injection vplunger, a scavenging pump mounted on the easing, said casing beingprovided with a drain conduit for collecting leakage fuel incommunication with the scavenging pump, conduit means in communicationwith a source of air at atmospheric pressure being also provided fordrawing air into the scavenging pump to maintain sub stantiallyatmospheric pressure in the leakage 4. A drainage system for fuelinjection pumps having a plurality of movable elements working againstfluid under high pressure comprising leakage collecting means adjacenteach element through which it is possible for leakage to occur,

drainage means connecting said'collecting means,

a positive displacement scavenging pump having an inlet, conduit meansfor delivering the collected fuel to. said inlet, an outlet conduit fromthe scavenging pump, and an air vent line connected with the scavengingpump inlet whereby pressure in the 'drainagemeans is maintained atsubstantially atmospheric pressure.

5. A drainage system for fuel injection pumps 1 having a plurality ofmovable elements working against fluid under high pressure comprising 16. In a drainage system for fuel injection pumps having a casing withdriving means and an injection-plunger unit mounted therein, said fuelcollecting conduit, and means for returning system.

2. In a fuel injection pump having a casing, a high pressure injectionplunger mounted therein, a driving shaft and in combination therewith, alow pressure fuel supply pump mounted on said casing, means forsupplyingfuel to the inlet of said pump, means for conducting fuel underpressure from the pump to the injection plunger, a scavenging pumpmounted on the casing at a low level thereon, said casing being providedwith a drain conduit in communication with the scavenging pump fordelivering leakage fuel thereto by gravity, conduitmeans incommunication -with a source of air at atmospheric pressure being alsoprovidedfor di'awing air into the scavenging pump to maintainsubstantially atmospheric pressuregin the leakage fuel collecting fuelfrom said scavenging pump to the fuel supply means, and means forreturningfuel from said scavenging pump to the fuel supply system.

3. In a fuel injection'pump having a casing,

driving means within the casing, a high pressure injection plungermounted therein and driven by said means, a fuel supply pump mounted onsaid casing and driven by the drlving'means, means for supplying fuel tothe inlet of said pump and means for conducting fuel under pressure fromtion with a source of air at atmospheric pressure being also providedfor drawing air 'into the scavenging pump to maintain substantiallyatmospheric pressure in the leakage fuel' collecting means, and meansfor returning fuel from said scavenging pump to the fuel supply system.

casing serving as a lubricant reservoir, the combination ofleakagecollecting means adjacent each element through which it is possible forleakage to occur, said means being independent of the lubricantreservoir, drainage means connecting said collecting means, a scavengingpump I casing serving as a lubricant reservoir, the combination ofleakage collecting means adjacent each element through which it ispossible for leakage to occur, said means being independent of thelubricant reservoir, drainage means connecting said collecting means, ascavenging pump having an inlet, conduit means for delivering thecollected fuel by gravity flow to said inlet, a fuel supply tank, anoutlet-conduit from the scavenging pump extending into said'tank andterminating at a level above-the maximum fuel level therein, and an airvent conduit connected with the scavenging pump inlet' and with the tanabove the maximum fuel level therein.

8. In a fuel injection pump construction, a unitary casing having. ahorizontal top face, a vertical bore formed in the casing from saidface, a removable injection plunger unit including inlet and-outletconduits fitted on the top of the casing and depending. within saidbore, a drive shaft rotatably mounted in the casing, a

. plurality of bores extending: downwardly from the top face of thecasing, tappet members mounted for reciprocation in said bores, saiddrive shaft being provided with cams engageable with said tappetmembers, a fuel distributor unit removablymountedvon the top face of thecasing over said tappetmenibers, a driving shaft rotatably mounted inthe casing parallel to the tending downwardly from the top surface ofthe drive shaft, gearing for driving said shaft from the drive shaft,and cam means carried by said shaft for operatingthe plunger unit.- I

9.- m a fuel injection pump construction, a unitary casing having asingle surfaced face, a vertical bore formed in the casing from saidface, a removable injection plunger unit fitted on said face anddepending within said bore, a drive shaft rotatably mounted 'in thecasing, a

plurality of bores extending downwardly from the face of the casing,tappet members mounted.

for reciprocation in said bores, said drive shaft being provided withcams engageable with said tappet members, a fuel distributor unitremovably mounted on the face of the casing over said tappet members, adriving shaft rotatably mounted in the casing parallel to the driveshaft, gearing for driving said shaft from the drive shaft, and cammeans carried by'said shaft for operating the plunger unit.

10. In a fuel injection pump construction, a unitary casing having ahorizontal top face, a vertical b'ore formed in the casing, a removableinjection plunger unit fitted on the top face of the casing anddepending within said bore, a drive shaft rotatably mounted in thecasing, a plurality of bores extending downwardly from the top face ofthe casing, tappet members mounted for reciprocation in said bores, saiddrive shaft being provided with cams engageable with said tappetmembers, a fuel distributor unit removably mounted on the top face ofthe casing, said unit being formed with conduits for delivering fuel toa plurality of cylinders and a common supply conduit, valves carried bysaid distributor unit positioned to control the conduits therein, saidvalves being positioned to be engageable bythe tappet members, a drivingshaft rotatably mounted in the casing parallel to the drive shaft,gearing for driving said shaft at a speed which is a multiple of thespeed of the drive shaft equivalent to the number of distributor valves,and cam means carried by said shaft for operating the plunger.

11. In a fuel injection pump construction, a unitary casing having asurfaced face, said casing being provided with a partition wall, a boreformed in the casing in the partition wall thereof, a removableinjection plunger unit fitted on the face of the casing and dependingwithin said bore, a tappet member mounted in said bore for driving theplunger unit, a drive shaft rotatably mounted in the casing, a pluralityof bores extending from the face of the casing, tappet members mountedfor reciprocation in said bores, said drive shaft being provided withcams engageable with said tappet members, a fueldistributor unitremovably mounted on the face of the casingover-said tappet members, adriving shaft rotatably mounted in the casing parallel to the driveshaft, gearing for driving said shaft from the drive shaft, and cammeans carried by said shaft for operating the plunger driving tappetmember.

12.In a fuel injection pump construction, a unitary casing having ahorizontal face, said casing being provided with a vertical partitionwall, a vertical bore formed in the casing in the partition wallthereof, a removable injection plunger unit fitted on the top of thecasing and depending within said bore, a. second bore formed in thepartition in alinement with the first named bore, a tappet cup mountedin said bore for driving the plunger unit, a drive shaft rotatablymounted in the casing, a plurality of bores excasing. t ppet membersmounted for reciprocationin said bores, said drive shaft being providedwith cams engageable with said tappet members, a fuel distributor unitremovably mounted on the topisurface of the casing over'said tappetmembers, a driving shaft rotatably mounted in the casing parallel to thedrive shaft, gearing for driving said shaft from the drive shaft, andcam means, carried by said shaft for operating the plunger drivingtappet member.

13, In a fuel injection pump construction, a unitary casingforming'alubricant reservoir having a horizontal top face, said casingbeing provided with a vertical partition wall, a vertical bore formed inthe casing in the partition wall thereof, a removable injection plungerunit fitted on the top face of the casing and depending within saidbore, a tappet member mounted in said bore for driving the plunger unit,a drive shaft rotatably mounted in the casing, a plurality of boresextending downwardly from the top face of the casing, tappet membersmounted for reciprocation in said bores, said drive shaft being providedwith cams engageable with said tappet members, a fuel distributor unitremovably mounted on the top face of the casing over said tappetmembers, said unit being formed with conduits for delivering fuel to aplurality of cylinders and a common supply conduit, valves carried bysaid distributor unit positioned to control they conduits therein, saidvalves being positioned to be engageable by the tappet members, adriving shaft rotatably mounted in the casing'parallel to the driveshaft and extending beyond the partition wall, gearing atone end of thecasing for driving said shaft from the drive shaft, cam means vcarriedby said shaft for operating the plunger driving tappet member, anauxiliary pump unit mounted on the casing at the end opposite thegearing, said unit including a supply pump and an independent scavengingpump, means for driving said pumps from the extending portion of thedriving shaft, I

means for supplying fuel to the supply pump and therefrom to theinjection plunger unit, and means independent of the lubricant reservoirfor delivering leakage fuel from the distributor valves and theinjection plunger unit to the scavenging. pump.

14. In a fuel injection pump construction, a unitary casing having ahorizontal top face, said casing being provided with a verticalpartition wall, a vertical bore formed in the casing in the partitionwall thereof, a removable injection plunger unit fitted on the top faceof the casing and depending within said bore, a tappet member mounted insaid bore for driving the plunger unit, a drive shaft rotatably mountedin the cusing, a plurality of bores extending downwardly from the topface of the casing, tappet members mountedfor reciprocation in saidbores, said drive shaft being provided wtih cams engageable with saidtappet members, a fuel distributor unit removably mounted on the topface of the casing over said tappet members, said unit being formed withconduits for delivering fuel to a plurality of cylinders and a commonsupply conduit, valves carried by said distributor unit positioned tocontrol the conduits therein, said valves being positioned to beengageable by the tappet members, a driving shaft rotatably mounted inthe casing parallel to the drive shaft and extending beyond thepartition wall,

gearing at one end of the casing for driving said shaft from the driveshaft, cam means carried by said shaft for operating the plunger drivingtappet member, an auxlliarypump unit mounted on the casing at the endopposite'the gearing, and means-for driving and unit from the extendingportion of the driving shaft.

15. In a fuel injection pump construction, a unitary casing having ahorizontal top face, said casing being provided with a verticalpartition wall, a vertical bore formed in the casing in the partitionwall thereof, .a removable injection plunger unit fitted on the top ofthe casing and depending within said bore, a second bore of smallerdiameter formed in the partition in alinement with the first named bore,the difference in diameter of said bores providing a leakage collectingchannel, a tappet member mounted in said bore for driving the plungerunit, a drive shaft rotatably mounted in the casing, a plurality ofbores extending downwardly from the top face of the casing, tappetmembers mounted for reciprocation in said bores, said drive shaft beingprovided with cams engageable with said tappet members, a fueldistributor unit removably mounted on the top face of the easing oversaid tappet members, said unit being formed with conduits for deliveringfuel to a plurality of cylinders and a common supply conduit, valvescarried by said distributor unit positioned to control the conduitstherein, said valves being positioned to be engageable by the tappetmembers, a driving shaft rotatably mounted in the casing parallel to thedrive shaft, gearing for driving said shaft from the drive shaft, cammeans carried by said shaft for operating the plunger driving tappetmember, a scavenging pump mounted on the casing, means for driving saidpumps from the driving shaft, and means for delivering leakage fuel fromthe collecting channel to the scavenging pump.

16. In a fuel injection pump construction, a unitary casing providedwith a vertical partition wall, a vertical bore formed in said wall, aremovable inJection plunger unit fitted on the top of the casing anddepending within said bore, a second bore formed in the partition inalinement with the first named bore, a tappet cup mounted in said borefor driving the plunger unit, a. drive shaft mounted in the casing, oneend thereof being supported by one end of the casing, said partitionwall being provided with a shallow bore coaxial with the drive shaft andproviding a bearing for the inner end of said shaft, a plunger drivingshaft mounted in the casing parallel to and below the drive shaft androtatably supported by bearings in one end wall of the casing and in thepartition wall, and gearing for driving said shaft from the drive shaft.

17; In a fuel injection pump construction, a unitary casing having avertical wall formed with an attaching face, said casing being providedwith a vertical partition wall, a vertical bore formed in the casing inthe partition wall thereof, a removable injection plunger unit fittedonthe top of the casing and depending within said bore, a second boreformed in the partition in alinement with the first named bore. a tappetcup mounted in said bore for driving the plunger unit, a drive shaftmounted in the casing being supported by a bearing at the attaching endof the casing and a bearing in the partition wall, a plurality of boresextending downwardly from the top surface of the casing, tappet membersmounted for reciprocation in said bores, said drive shaft being providedwith cams engageable with said tappet members, a removable fueldistributor unit removably mounted on the top surface of the casing,said unit being formed with conduits for delivering fuel to a pluralityof cylinders and a common supply conduit, valves carried by saiddistributor unit positioned to control the conduits therein, said valvesbeing positioned to be engageable by the tappet members, a driving shaftmounted in the casing parallel to the drive shaft and rotatablysupported by bearings with one end wall of the casing and in thepartition wall, gearing for drlvingsaid shaft from the drive shaft, saiddriving shaft extending beyond the partition wall. an auxiliary pumpunit mounted on the casing at the end opposite the attaching surface,said unit including a supply pump and a scavenging pump, means fordriving said pumps from the extension of the driving shaft, means forsupplying fuel to the supply pump and therefrom to the injection plungerunit, and means for delivering leakage fuel from the distributor valvesand theinjection plunger unit to the scavenging Dump.

18. In a fuel injection pump construction, a unitary casing providedwith a partition wall providing support for bearings, a bore formed inthe casing in the partition wall thereof, a removable injection plungerunit fitted on the casing and depending within said bore, a drive shaftmounted in the casing being supported by a bearing at one end of thecasing and a bearing in the partition wall,a driving shaft mounted inthe casing parallel to the drive shaft and rotatably supported bybearings at one end wall of the casing and in the partition wall,gearing for driving said shaft from the drive shaft, a centrifugalgovernor carried by the driving shaft, 9. plunger control member mountedfor reciprocation in the partition wall, and control linkage operativelyconnected to the governor and the control member.

19. In a fuel injection pump construction, a unitary casing beingprovided with a partition wall providing support for bearings, a boreformed in the casing in the partition wall thereof, aremovable injectionplunger unit fitted on the casing and depending within said bore, adrive shaft mounted in the casing being supported by a bearing at oneend of the casing and a bearing in .the partition wall, a driving shaftmounted in the casing parallel to the drive shaft and rotatablysupported by bearings at one end wall of the casing and in the partitionwall, gearing for driving said shaft from the drive shaft, a centrifugalgovernor carried by the driving shaft, a plunger control, member mountedfor reciprocation in the partition wall, and a control memberoperatively connected to the governor and the control member, saidmember being pivoted on a transverse axis between the shafts.

20. In a fuel injection pump construction, a

unitary casing having ahorizontal top face, a.

vertical bore formed in the casing, a removable injection plunger unitfitted on the top of the casing and depending within said bore, a secondbore of smaller diameter formed in the casing in alinement with thefirst mentioned bore, the difierence in diameter in said bores providinga leakage-collecting channel, a tappet member mounted in said smallerbore for driving the plunger unit, a plurality of bores extendingdownwardly from the top face ofthe casing, tappet members mounted forreciprocation in said bores, means for operating said tappet members,said casing being formed with leakmembers and including distributionvalves and age-collecting channels around the top-of said distributionconduits, a scavenging pump mounttappet members, a leakage-collectingchannel in ed on the casing, and means for delivering leakcommunicationwith said channels and with the age fuel from the leakage-collectingchannels to leakage-collecting channels in the plunger unit 5 saidscavenging pump.

bore, a fuel distributor unit removably mounted EDWARD A. JOHNSTON.

on the top face of the casing over said tappet RAYMOND E. PETERSON.

